1. Field of the Invention
The present invention relates to a remote control system for a vehicle which can automatically lock and unlock the door(s) of a vehicle in wireless communication and more particularly to a remote control system for a vehicle which can automatically lock the door(s) of a vehicle when a user (driver) who carries with him an electronic or entry key (with a portable transmitter/receiver) which includes an identification code assigned to the vehicle walks away a predetermined distance from the vehicle and automatically unlock the same when the user comes back to the distance.
2. Description of the Related Art
Lock/unlock remote-control systems for vehicle doors are known having a so-called, xe2x80x9cwelcome functionxe2x80x9d. In the systems, every user (driver) of a vehicle owns an entry key (with a portable transmitter/receiver) which upon receiving a response demand signal that is transmitted from a transmitter installed in the vehicle and is receivable within a predetermined range about the vehicle (which may be referred to as xe2x80x9chaving a predetermined communication areaxe2x80x9d hereinafter), can transmit a response signal carrying a unique identification code assigned in advance to each vehicle. When the user walks away from the predetermined range of the vehicle and its entry key is disabled to receive the response demand signal and thus to transmit back the response signal, the door of the vehicle is automatically locked. When the entry key moves into the predetermined range and its response demand signal is received by the transmitter/receiver which then responses thereto to send back a response signal, the door is automatically unlocked.
For example, some of such conventional xe2x80x9cwelcome functionxe2x80x9d based lock/unlock remote-control systems for vehicle doors are disclosed in Japanese Patent Laid-open Publications (Heisei)5-106376 and (Heisei)10-25939 in which a transmitter mounted on a vehicle is provided for intermittently transmitting a response demand signal having a predetermined communication area and, when receiving a signal responding to the response demand signal from an entry key which is carried by the user of a vehicle and moves into the predetermined communication area, examining whether the response signal is valid (regular) or not (welcome code examination). When the response signal has been examined to be valid, the door(s) of the vehicle is automatically unlocked. On the contrary, when the response signal is not valid or when the entry key stays out of the predetermined communication area and the vehicle-mounted transmitter receives no response signal, the door remains locked.
Accordingly, when the user of the vehicle carrying the entry key simply walks away from the predetermined range of the vehicle, the door of the vehicle can automatically be locked without paying any attention to or operating the entry key. When the user comes into the range, the door can automatically be unlocked. This requires no boresome actions of unlocking the door for riding the vehicle as well as contributes to the prevention of failing to lock door(s), and of vehicle theft.
The conventional systems have some advantages, particularly once the communication area is preset to a smaller size (for example, one meter in radius), the systematic locking of the door can easily be confirmed after getting off the vehicle, the power consumption for transmitting signals can be as small as not hostile to a battery, and the ID code (uniquely assigned to a vehicle) can hardly be intercepted by any other parties. The locking of the door may be easily confirmed by auditorily and visually perceiving the sound of a door locking mechanism and the shift of an inside door lock knob to the lock position.
Another conventional system disclosed in Japanese Patent Laid-open Publication (Heisei)10-153025 is provided in which a transmission antenna for detecting the approaching of an object into a middle-sized area around a vehicle is mounted on the vehicle in addition to an antenna for transmitting the response demand signal. Upon detecting the approaching of the object or a driver into the middle-sized area, the vehicle releases the response demand signal with a small-sized predetermined communication area and, when receiving a response signal to the response demand signal from the entry key of the right driver, unlock the door. Also, a second transmitting means having a greater communication area is provided for locking the door. The door is thus locked when the communication to the entry key with the second transmitting means is disabled.
According to the conventional systems, when the communication area for the response demand signal is set to be wide enough to detect the driver approaching into the area of the vehicle at an earlier occasion, the door(s) can be unlocked positively before the driver reaches the vehicle. This eliminates the need of the door being unlocked by the driver or user and provides the ease of getting in the vehicle with operating only a door outer handle, hence improving the utility.
However, as the communication area is wide, the locking of the door will be carried out only when the user departs further from the vehicle, hence causing the user to confirm the door locking (through listening to the sound of the door locking mechanism or viewing the shift of the inside door lock knob to the lock position) with much difficulty. Also, while the user with the entry key walks about or pursues a job (e.g. ordering throughout the trunk room), the door locking is not performed and it may fail to protect articles in the vehicle from a thief.
In particular, when the user with the entry key is departing from the vehicle, its back is often turned to the vehicle. The wider the predetermined communication area, the longer the period of the door remaining unlocked is extended and thus the higher the risk of being thieved will be increased. Also, the wider communication area requires a higher level of power for transmitting the response demand signal and the power consumption will be soared up drawing more power from the battery.
For compensation, a modification is proposed such as disclosed in Japanese Patent Laid-open Publication (Heisei)10-25939, where the communication area is reduced (about one meter in radius) allowing the response demand signal to be not received in a shorter distance from the door thus to lock the door. This permits the door locking to be easily confirmed, the ID code (ID number) to be hardly intercepted, and the power for signal transmission to be minimized, hence lowering the power consumption.
However, the above modification will hardly ensure the unlocking of the door. It is common in the art for minimizing the power consumption for transmitting the response demand signal that the response demand signal from the vehicle is usually transmitted intermittently. With the wider communication area, the user moving in the wider area is able to communicate with the vehicle, even if the response demand signal is transmitted with longer intermission period. Accordingly, the door is surely unlocked before the user arrives at the vehicle.
With the smaller communication area, however, when the user rushes to the vehicle in less time through the communication area, the communication between the vehicle-mounted transmitter and the entry key may not be completed until the user arrives at the vehicle. This causes the door to remain locked and its door outer handle may have to be operated a number of times without success. As a result, the entry key system will be lost in commercial value. As a further modification, the period of the intermittent transmission of the response demand signal may be shortened. This will however increase the power consumption and cause more power be drawn from the battery.
On the other hand, the conventional system disclosed in the above-mentioned Japanese Patent Laid-open Publication (Heisei)10-153025 allows the power for transmitting the response demand signal to be possibly decreased, but it requires the extra transmission antenna for detecting the invading of an object, hence increasing the complexity of the overall arrangement and thus the cost of the system. Also, the power consumption will be increased by the additional equipment. Moreover, the above system transmits the response demand signal even when any other personal or creature than the right entry key (user) advances close to the vehicle, hence requiring more improvement for the power consumption. Since the communication area is too small to examine whether the entry key is right or not as required before accepting the unlocking, the door may remain not unlocked when the user or driver rushes to and arrives at the vehicle. This will result in the misconduct of the automatic unlocking function.
An object of the present invention is to provide a remote control system for a vehicle which can predictably control a vehicle mounted device such as a door of the vehicle corresponding to the distance from the vehicle to an entry key.
As a first feature of the present invention, the remote control system for a vehicle comprises: a transmitter mounted on the vehicle for transmitting a plurality of response demand signals which are receivable within different sizes of a predetermined range outside the vehicle; a portable transmitter/receiver for receiving the response demand signals and sending back a response signal; a receiver mounted on the vehicle for receiving the response signal sent back from the portable transmitter/receiver; and a controlling means for controlling vehicle-mounted components corresponding to the reception of the response signal by the receiver, wherein said controlling means are arranged to control at least either unlocking or locking of the door(s) of the vehicle depending on whether the response signal to a type of the response demand signal other than a particular response demand signal being receivable in the largest size of the predetermined range is received or not by the receiver.
As a second feature of the present invention, the transmitter intermittently transmits different types of the response demand signals receivable within corresponding sizes of the predetermined range, and the controlling means identifies a particular predetermined range where the portable transmitter/receiver is located on the basis of the interval between receptions of the response signals and controls the vehicle-mounted components in a predetermined mode, corresponding to the size of the predetermined range where the transmitter/receiver is located.
As a third feature of the present invention, various types of response demand signals are intermittently transmitted at different intervals such that the transmission of one type of the response demand signal receivable within a smaller predetermined range is transmitted at least once between two adjacent transmitted timings of another type of the respond demand signal receivable in a wider predetermined range.
As a fourth feature of the present invention, the response signals sent back from the portable transmitter/receiver are discriminatable one another according to which size of the predetermined range of the respond demand signal that the respond signals respond to.
As a fifth feature of the present invention, when the disembarkation of the user is detected and the user is departing from the vehicle, a type of the response demand signal receivable within the smallest size of the predetermined range is transmitted from the transmitter, and when the response signal showing reception of the response demand signal receivable in the smallest size of the predetermined range is no more received by the receiver mounted on the vehicle, another type of the response demand signal receivable within the second smallest size of the predetermined range is begun to be transmitted from the transmitter and, in a similar manner, when the response signal to a type of the response demand signal receivable in a relatively smaller size of the predetermined range is no more received by the receiver mounted on the vehicle, a further type of the response demand signal receivable within a relatively larger size of the predetermined range is begun to be transmitted in sequence from the transmitter.
As a sixth feature of the present invention, when the entry key is approaching to the vehicle and the response signal to the type of the response demand signal receivable within the largest size of the predetermined range is first received by the receiver mounted on the vehicle, the response demand signal receivable within second largest size of the predetermined range is transmitted from the transmitter and then a response demand signal receivable within a relatively smaller size of the predetermined range is transmitted in sequence from the transmitter.
As a seventh feature of the present invention, when the embarkation of the user is detected by the embarkation detecting means, a type of the response demand signal receivable within the vehicle is transmitted from the transmitter.
According to the first feature of the present invention, the distance from the vehicle to the user carrying the portable transmitter/receiver (entry key) can precisely be identified thus to control the vehicle mounted device such as the door(s) at an optimum length of the distance, hence improving the utility of controlling the vehicle mounted device such as unlocking and locking the door is compatible with the anti-thief function.
According to the second feature of the present invention, the distance range from the vehicle to the user carrying the portable transmitter/receiver can be identified on the basis of the interval between receiving timings of the sent-back response signal on the vehicle even if characteristic codes included in the response signals are not different each other, which response signals are sent back from the portable transmitter/receiver that responds to a plurality types of the response demand signal receivable within their respective sizes of the predetermined ranges which are different each other. Hence, the vehicle mounted device can favorably be controlled depending on the distance as well as the construction of the transmitter of the portable transmitter/receiver and the code identifying action of the controlling means on the vehicle can significantly be simplified.
According to the third feature of the present invention, the response signal is also intermittently released from the portable transmitter/receiver, thus providing the same effects and advantages as described just above.
According to the fourth feature of the present invention, as the response signals released from the portable transmitter/receiver in response to reception of the response demand signal are different each other based on the different sizes of the receivable ranges of the demand signals, the distance from the vehicle to the portable transmitter/receiver can be identified only from the response signal received and the optimum control of the device mounted on the vehicle can be performed in accordance with the distance.
According to the fifth and sixth features of the present invention, at the disembarkation of the user, as the portable transmitter/receiver carried by the user departs far from the vehicle, the transmission of the response demand signal receivable in a wider size of the predetermined range is executed in sequence and the transmission of the response demand signal receivable in a smaller size of the predetermine range is canceled. As the potable transmitter/receiver comes from far towards the vehicle, on the other hand, the transmission of the response demand signal with a relatively smaller predetermined receivable range is not executed before the response signal responding to the response demand signal with a relatively larger predetermined receivable range is received by the vehicle.
More particularly, while the portable transmitter/receiver is out of the largest predetermined receivable range, the response demand signal receivable in the largest predetermined range only is transmitted. Only when the response signal responding to the response demand signal receivable in the largest predetermined range is received by the vehicle, the transmission of the response demand signal being receivable in a smaller size of the predetermine range and used for actually controlling the unlocking and locking of the door is executed. Therefore, the transmission of the response demand signal is minimized hence reducing the consumption of a power from a battery equipped on the vehicle.
According to the seventh feature of the present invention, the user carrying the portable transmitter/receiver in the vehicle can readily be acknowledged, and the vehicle mounted device in the vehicle is controlled on the basis of the response signal from the portable transmitter/receiver responding to a particular type of the response demand signal receivable within the vehicle, hence improving the anti-thief function.